Newby to cell phone forensics needs help with next school

Hello,
I was recently able to get certified in Cell Phone Tech and Forensic Data Recovery with the Public Agency Training Council. While I enjoyed these classes I know that they only hit on basics. For my next school I was thinking of something that might discuss specifics on how a cell phone works and where and how data is stored on them. I know that there are many different types of operating platforms, but there must be some fundimentals. I would greatly appreciate any suggestions. I'm sort of leaning towards a one week class if possible and free is always good, but don't let that stop you from suggesting.

Many thanks,

Ed